Apparatus and process for processing strip material



Aug. 17, 1965 A. TIX 3,200,624

APPARATUS AND PROCESS FOR PROCESSING STRIP MATERIAL Filed Feb. 14. 1962 INV ENT OR ARTHUR T/X United States Patent many Filed Feb. 14, I962, Ser. No. 173,863 Claims priority, application Germany, Feb. 15, 1%1,

13 Claims. for. 72-19 This invention relates to processes and apparatus for treating strip material and more particularly to processes and apparatus for rolling strips to predetermined sizes.

It is a general object of the invention to provide improved processes and apparatus for the handling of strip materials.

In a continuous mill wherein material to be rolled extends simultaneously through a plurality of rolling stations such as, for example, in a roughing mill or in a finishing mill, the procedure can be considered as a single pass or operation with forward and backward slips corresponding to neutral points in turn corresponding to the stations.

In a continuous mill, in which the material in the form of a strip sags between two stations to form a loop, deviations in the desired system of forward and backward slips and associated roller speeds may be corrected, for example, by loop lifters which influence the speed of the rollers of one of the stations. This change in speed propagates like a disturbance wave to one or the other end of the mill and further loop lifters of the mill compensate for the disturbance. A state of equilibrium is thus established based on the velocity pattern of the op eration taking into account the forward and backward slips.

In continuous mills in which the processed strip is too thick to permit the formation of a loop between stations, deviations cause tensile or compressive forces in the intermediate sections of the strip. Known mills of this type cannot balance out the deviations and there occur harmful influences, especially on the quality of the surface of the strip. Moreover, this requires serious consideration of the driving power for the rollers of the individual stations which must be taken into account in the layout of the stations and their drives. Such mills it is known, can be driven only far below the rated load.

It is an object of the invention to provide means and techniques to keep strips almost or completely free from tensile and compressive forces even in continuous mills in which a loop lifter control cannot be effectively applied. The invention relates particularly to continuous roughing trains for hot strip mills, but is as well applicable in the continuous trains of section mills wherein loop lifters or the like cannot be used or can be used only under special conditions.

According to the invention, a change of the driving moment, which is measured at one station, on elastic driving elements and which occurs after the strip has entered the respectively sequential station, is used for the purpose of influencing the speed of the first station in such a manner that the change in torque is counteracted. The preferred method is to influence the speed of the station upstream relative to the direction of rolling, so that a disturbance at a neutral point is balanced toward the upstream end of the mill.

A feature of the process according to the invention consists of the use of elastic or resilient driving elements for measuring torque deflections. Further, it is important to have comparatively long elastic paths to make it possible to determine the torque changes very accurately.

It is possible to use elastic driving elements in indeendent mill stations. For this purpose an intermediate 3,2Wfi24 Patented Aug. 17, 1%65 shaft developed as a torsion bar spring may be connected in series with a coupling or clutch including driver spiders having arms mounted between coil springs which move (as will be shown) in their axial direction on the circumference of a circle about the shaft axis. Such elastic drives produce a particularly good quality surface on the associated strip.

However, the invention is not limited to the abovedescribed spring combination, it being possible to use only the torsion bar springs or only the elastic couplings or clutches in addition to the two elements being coupled together in series.

According to the invention, the torque may be measured by optical, mechanical or electrical measurement of the corresponding spring elongations. Especially advantageous is the measuring of the related force by means of electric pressure meters which are arranged between the spider arms and the coil springs of the clutches. Further, in order to eliminate errors in measurement due to the required collecting ring transmission of the comparatively weak current pulses which result, amplifiers may, according to the invention, be built into the coupling clutch.

As indicated above, it is important to measure the changes in torque as accurately as possible. In continuous roughing trains for strip material of very different width, the invention provides further for varying the sensitivity range of the measuring instruments. For example, if a narrow strip instead of wide strip is rolled on a given train, the torque level is located at the lower limit of the range of the motor power.

Errors in measurements have a comparatively strong effect on the accuracy of the speed control. Unfortunately, in this regard, not only is the width of the strip a criterion of the torque level, but as well the temperature and the kind of alloy have an effect on the torque level. According to the invention, all these influences which are simply the resistance to deformation of the strip are measured by the torque meter of the first station before the strip arrives at the second station of the train. The invention provides for effecting a sensitivity control for the torque measurements of all stations of the mill automatically in accordance with the torque indication at the first station.

The above objects and features of the invention, as well as advantages thereof will appear from the following detailed description of a preferred embodiment as illustrated in the accompanying drawing in which:

FIGURE 1 diagrammatically represents a mill including a sequence of rolling stations in accordance with the invention;

FIGURE 2 diagrammatically illustrates the progression of a strip through a sequence of rollers;

FIGURE 3 diagrammatically illustrates a particular control contemplated in accordance with the invention;

FIGURE 4 is a sectional view taken along line IV IV of FIG. 3.

In FIGURE 1 of the drawings is diagrammatically represented an ingot or strip 10 adapted to be processed by a linear sequence of the rolling stations 12, I4, 16, i8, 20 and 22.

The operation of said rolling stations is effected in known manner to roll down the ingot to a strip of predetermined size.

Operatively associated with said rolling stations are individual DC. motors 24, 26, 28, 30, 32 and 34, each operating normally at a constant speed, said speed being determined in accordance with a velocity pattern which is established in accordance with well known principles.

In accordance with the invention there is associated with the coupling arranged between the various motors 3 and the associated rolling stations, torque indicating means or meters 36, 38, 4t 42, 44 and 45.

As will be described in greater detail hereinafter, it is the purpose of the elements 36-45 to measure changes in torque or the torque variances in the aforesaid coupling mechansirns in order to control the speed of the motor of the next sequential upstream motor.

For this purpose torque meter 38 is coupled to motor 24 by a line 46; torque meter 40 is coupled to motor 26 via a line 48; torque meter 42 is coupled via line 59 to motor 28; torque meter 44 is coupled to motor 36 via line 52 and torque meter 45 is coupled to motor 32 by line 54. In particular the lines 46 to 54- inclusive feed current to motors 2-4 to 32 respectively to control either field intensity or armature current in a well known manner.

The torque meters 36-45 may be conventional meters adapted, for example, for converting electrical signals into mechanical movements or into control signals in accordance with conventional techniques. Also, in accordance with conventional techniques, said meters may have a controllable sensitivity.

According to a further feature of the invention, there is provided a sensitivity control member 56 which may, for example, take the form of a computer of conventional type. This sensitivity control has an input electrically coupled via line 57 to the torque meter 36, to be controlled thereby, and may further be electrically connected to the aforesaid torque meters by means of connections 58, 60, 62, 64, 66 and 68. Sensitivity control 56 receives signals from torque meter 36 indicative of the torque at rolling station 12 and converts these signals to signals proportional to the received signal which are transmitted to torque meters 38 to 45 for adjusting their sensitivity. The purpose of the control 56 will'become hereinafter apparent.

Referring next to FIGURE 2 of the drawing, it is seen that the ingot or strip passes progressively in an upstream to downstream direction through the rollers '79 and 72 constituting the first rolling station and thence between the rollers 74 and '76 constituting the next sequential downstream rolling station. In FIG. 2 the strip 10 has not yet become engaged between the rollers 78 and 8t) of the next sequential downstream station.

Referring next to FIGURE 3, this figure illustrates by way of example, and in diagrammatic form, some of the details of, for example, rolling station 14 and the associated motor 26, the torque meter 38 being evident in this figure along with the ingot or strip 10 and the associated rollers 74 and 75.

In addition are illustrated the spindles 82 and 84, which respectively support rollers 74 and 76, and as well the drive transmission 86 which is coupled to said spindles for driving the same. Additionally, the apparatus of FIG. 3 comprises a shaft 88 connected to the drive transmission 86 for driving the same and collector rings 99 which are electrically conductive elements, the purpose of which will become hereinafter apparent.

Connected to shaft 88 is a coupling member 92 which is effective to connect shaft 88 to torsion bar 94, connected by means of rigidly connected flanges 96 and 98 to the shaft of motor 26. It is to be understood that the other stations of the apparatus are similarly composed.

In FIG. 4 is shown a sectional view through line IV-IV of'FIG. 3, and more particularly, there is disposed in this figure some of the constructional details of the coupling member 92.

Couplingmember 92 comprises rotatively displaceable elements or parts 1% and 102, concentricallydisposed on a common axis of rotation. These parts are provided respectively with interdigitated radially extending sections 1M and 106, between which are serially disposed co1l springs 188 and pressure responsive elements 110.

Pressure responsive elements 110 are adapted to proof the train or sequence of stations.

Vida or generate electrical signals in accordance with the forces or pressuresexerted thereagainst. These elements are connected to amplifiers 112 mounted on one of the rotatably displaceable elements such as, for example, the elernent 102.

' Amplifier 112 is provided with power supplied through selected of the rings W, whereas other of said collector rings are adapted to remove amplified electrical signals which have been processed through the associated amplifier 112.

It will appear from FIGURE 4 that ar'otationaldisplacement between radially extending parts res and 1% is reflected by a compression of springs 168 and therefore by an increased pressure exertedagainst elements Hit so that a signal can be generated thereby in conventional manner. Crystal including elements responsive to pressure or varying electrical signals are well known which are suited to this purpose.

if an ingot or slab it) to be rolled is seized by the first station 12, the torque meter 36 of said station unergoes a wide deflection, but then fades away to a stationary state. 1 This is a measure of the distance load By control 56, the torque meter 36 adjusts the sensitivity range of all of the torque meters of the train to the level of the distance load, inclusive of its own sensitivity range as well. The zero point of the torque meter 36 of the first station 12, which quickly becomes finely adjusted by the sensitivity setting, persists until the front endof the strip enters the secondstation 14. At this time the torque meter 33 measures the reaction of the entering impact. A delaying control element (not shown) provides that, only after said impact has faded awa, can the torque meter exert an influence on the speed of rotation of the rollers of the first station. For example, if the predetermined speed of thesecond station in the pattern of the forward and backward slips of the neutral points of the two stations remainscorrect, the torque meter automatically assumes its zero setting after said iniial impact. But if'the rollers of the second station run slightly to quickly, the strip between the two stations exerts a draft force (tension) or pull on the first station with the result that a disturbance towards the negative is imparted relative to the zero setting of meter 38; The disturbance is electrically communicated to the speed con trol instrument (not shown) of the motor. 24 and has the 1 effect of increasing the speed of the rollers 70 and 72 somewhat too slowly, the torque meter 38 adjusts the resulting disturbance positively by a reduction in speed of the rollers of the first station.

It the front end of the strip then enters the third station, the torque meter'of the second station reacts accordingly to a draft or thrust force of the stripsection between the second and third stations. This means that the torque meter of the'second station is adjusted after the strip has entered the second station and before it has entered the third station and after the first station has been adjusted to azero point which it tends to maintain, because it is. arranged in a regulating circuit of its driving motor. In response to the disturbance communicated to it from the third station by the draft or thrust force of the strip, the torque meter of thesecond station increases or reduces the speed of the rollers of the second station. This, in turn, causes the torque meter of the first station to react since the change in speed of the second station is a new positive or negative disturbance for the torque meter of the first station.

When the strip enters the fourth, fifth, and sequential stations, the above-described process is repeated in such a manner that, first, the speed of the first rearwardly located stationis adjusted, then, the speedof the second rearwardly located station and so on all the way back to the first station of the roughing train. Only when the strip is in all stations of the roughing train at the same time will there be a stationary state in the speeds of all stations. The adjusting of the speeds of the individual stations takes place in a practically inertialess manner almost simultaneously. The description of the successively acting adjustments in stages is merely intended to illustrate the mutual dependence of the speeds of the stands.

In order to avoid the result that the above-described stationary state be disturbed by short, jerky changes of the torque caused by irregularities of the strip, it is essential that the elastic driving elements react compartively softly. A torsion angle of 8 is for this very reason better than a torsion angle of only, say, 3. On the other hand, it is essential to measure the torque immediately ahead of the station and not only at the driving motor, since said motor with its sizeable flywheel moment introduces an unfavorably big inertia into the measuring operation. For the time intervals required by the strip for entering each following station are so short that the adjustment is as inertialess as possible. This presents no difficulties from the electrical angle. To measure the torque, if possible, at the moment of its origin requires no special measures, just those which the invention proposes by using the elastic drive.

There will now be evident to those skilled in the art many modifications and variations of the apparatus and process set forth above. These modifications and variations will not departing from the scope of the invention as defined by the following claims.

What is claimed is:

1. In association with a sequence of at least two rolling stations at each of which is located drive means which transmits power in the form of torque and speed for the purpose of applying rolling force to a continuous length of material passing from a first of said stations to the other of said stations, a method comprising measuring the torque at said first station to detect the influence of said length of material on the torque developed at said first station and establishing a detection level at the other of said stations in accordance with said influence; and measuring the influence of said length of material on the torque developed at one of the stations and varying the speed in another station in accordance with said influence.

2. A method as claimed in claim 1 comprising representing said influence as a magnitude of electrical energy amplifying said electrical energy and controlling the speed at the other said station with said amplified electrical energy.

3. A method is claimed in claim 1, wherein said rolling force is applied through a torsion bar, the method comprising detecting said influence at said torsion bar.

4. A method as claimed in claim 1, wherein said torque force is applied through coupling members including sections connected by coil springs, the method comprising detecting said influence at said coil spring.

5. In association with a sequence of at least two rolling stations at each of which is located drive means which transmits power in the form of torque and speed for applying rolling forces to a continuous length of material passing from a first of said stations to the other of said stations, a method comprising measuring the torque at said first station to detect the influence of said length of material on the torque developed at said first station, and establishing a detection level at the other of said stations in accordance with said influence.

6. A method as claimed in claim 5 wherein the length of material passes through a plurality of stations after said first station, the method further including controlling the speed delivered by the drive means at a station adjacent that one at which the influence on torque is measured in order to diminish such influence.

7. Rolling apparatus comprising a sequence of rolling stations including rollers aligned to process a continuous length of material, motors adapted for being coupled to the rollers of said stations to drive said rollers and thereby roll said strip and drive the same through said sequence of stations in an upstream to downstream direction, a drive transmission coupled to the rollers in each station, a shaft coupled to each said drive transmission, a coupling member on each said shaft, each coupling member including rotatively displaceable sections and coil springs and pressure sensitive elements serially arranged between said seconds, said elements being adapted to provide an electrical signal according to pressures exerted thereon, a torsion bar connected between each coupling member and the corresponding motor, amplifier means on and rotatable with each coupling member and connected to the associated element to amplify the signal thereof, collecting rings on each shaft for supplying power to the corresponding amplifier means and for removing the amplified signal therefrom, torque meters coupled via said rings to said amplifier means, the torque meter associated with each station being connected to one of the motors to control the same, and means connected to the torque meter of the first of the sequence of rolling stations and being controlled by the same to adjust the sensitivity of each of said torque meters.

3. Rolling apparatus comprising a sequence of rolling stations including rollers aligned to process a continuous strip, motors adapted for being coupled to the rollers of said stations to drive said rollers and thereby roll said strip and drive the same through said sequence of stations in an upstream to downtream direction, a drive transmission coupled to the rollers in each station, a shaft coupled to each said drive transmission, a coupling member on each said shaft and connected to the corresponding motor, means of each coupling member to provide a signal varying according to torque changes therein, and torque meters coupled to said means, the torque meter associated with each station being connected to one of the motors to control the same.

9. Rolling apparatus comprising a sequence of rolling stations including rollers aligned to process a continuous strip, motors adapted for being coupled to the rollers of said stations to drive said rollers and thereby roll said strip and drive the same through said sequence of stations in an upstream to downstream direction, coupling members connecting said rollers to the corresponding motors, and torque indicating means coupled to the coupling members to measure torque changes therein, the torque indicating means associated with each station being connected to one of the motors to control the same.

10. Apparatus as claimed in claim 9, wherein said cou pling members comprise torsion bars.

11. Apparatus as claimed in claim 9, wherein each said coupling member defines an axis of rotation and comprises two rotatively displaceable members including interdigitated radially extending parts, and a spring and pressure responsive member serially disposed between said parts.

12. Apparatus as claimed in claim 11, wherein said pressure responsive member is adapted to produce an electrical signal, comprising an amplifier on one of said parts and connected to the pressure responsive member.

13. Apparatus as claimed in claim 12 comprising collecting rings connected to the amplifiers.

References Cited by the Examiner UNITED STATES PATENTS 2,007,505 7/35 Smith 73-136 2,134,514 10/38 Heyman -35.l 2,332,859 10/43 Kreissig et a1 80-54 2,544,467 3/51 Michel 80-35.l 3,110,203 11/63 Stringer 8035 CHARLES W. LANHAM, Primary Examiner.

LEON PEAR, WILLIAM J. STEPHENSON,

Examiners. 

1. IN ASSOCIATION WITH A SEQUENCE OF AT LEAST TWO ROLLING STATIONS AT EACH OF WHICH IS LOCATED DRIVE MEANS WHICH TRANSMITS POWER IN THE FORM OF TORQUE AND SPEED FOR THE PURPOSE OF APPLYING ROLLING FORCE TO A CONTINUOUS LENGTH OF MATERIAL PASSING FROM A FIRST OF SAID STATIONS TO THE OTHER OF SAID STATIONS, A METHOD COMPRISING MEASURING THE TORQUE AT SAID FIRST STATION TO DETECT THE INFLUENCE OF SAID LENGTH OF MATERIAL ON THE TORQUE DEVELOPED AT SAID FIRST STATION AND ESTABLISHING A DETECTION LEVEL AT THE OTHER OF SAID STATIONS IN ACCORDANCE WITH SAID INFLUENCE; AND MEASURING THE INFLUENCE OF SAID LENGTH OF MATERIAL ON THE TORQUE DEVELOPED AT ONE OF THE STATIONS AND VARYING THE SPEED IN ANOTHER STATION IN ACCORDANCE WITH SAID INFLUENCE. 